Railway signaling.



R. A. McCANN. RAILWAY SIGNALING. APPLICATION FILED Aue.|9. m5.

R O T N E V N RONALD A. MGCANN, 0F SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH 8c SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY SIGNALING.

Specification of Letters Patent.

Patented qIuly'ft, 1917.

Application filed August 19, 1915. Serial No. 46,285.

To all whom it may concern:

tain new and useful Improvements in Railway Signaling, of which the following 18 a specification.

My invention relates to railway signaling, and particularly to signaling for stretches of single track over which trafiic moves in both directions, such for example, as stretches of single track between passing sidings.

I will describe one form of signaling system embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing a stretch of single track having applied thereto one form of signaling system embodying my invention.

Referring to the drawing, A-'B is a stretch of single track between two passing sidings E and moves in both directions. Traflic through this stretch from east to west is governed by signals S S and S located at intervals through the stretch, and trafiic through the stretch from west to east is governed by other signals S, S and S located also at intervals through the stretch. Hereinafter I shall call signals S and S the end sig nals and I shall refer to the, remaining signals as intermediate signals.

The stretch A-B is divided by insulated joints 3 into several successive sections A-(, C-D and D-B, and as here shown a pair of opposing signals is located near each junction of adjacent sections, although I do not wish to be limited to this particular location of the signals. Each section is provided with one or more track circuits including track relays for the control of the signals. As here shown, each section is divided by insulated joints 3 into two subsections, and each sub-section is provided with a separate track circuit. For example, section is divided into two sub-sections A II and l-I-C. Each traclccircuit comprises the railsof the sub-section, a battery b, and a track relay, the latter-being F, over which stretch traflic designated by the reference character T with the same exponent as that of the ad-' jacent signal which governs traffic through the corresponding sub-section.

For each signal I provide a signal relay for the control thereof, which relays are designated in the drawing by the reference character R with an exponent corresponding to the exponent of the signal which the relay controls. Each signal is provided with a circuit which is controlled by the corresponding signal relay. For example, the circuit for signal S is from battery B through wire 25, contact 15 of relay R wire 26, operating mechanism of signal S wire 27, contact 16 of relay R wire 29 to battery 13 Each of the other signals is provided with a circuit similar to that for signal S For purposes to be described hereinafter I.provide adjacent each intermediate signal an electromagnetic translating device designated by the reference character P with the same exponent as that of the corresponding signal. Each device. P is responsive only to reversals of the current through its energizing winding, and having once responde to current of one direction it remains in that position-even when deenergized-until it is energized by current in the opposite direction. I have here shown devices P to be polarized relays, but it. is understood that I do not wish to be limited to this particular type of electromagnetic translating device.

Each signal relay (except relays R and R) is controlled by both track relays for the section through which the corresponding signal governs traffic, and also by a front contact of the signal relay corresponding to the signal next in advance governing traffic in the same direction. For

example, relay R, which controls signal S, is provided with the following circuitfrom battery B through wire 25, contact 17 of relay R", wire 31, contact 21 of relay I", wire 32, contact 11 of relay T, wire 33, contact 12 of relay T, wire 34, relay R wires 35') and '29 and common wire 30 to battery E. The circuits for signal relays R R" and R are similar to that just traced for relay R. The circuits for signal relays signal relay.

R and R are similar to that just traced for relay R except that they are controlled only by the track relays for sections AC and D-B respectively.

It will be seen that as thus far described, each signal relay is controlled by the track relays for the section through which the corresponding signal governs trafiic, and also by the signal relay for the signal next in advance overning traiiic in the same direction. I-Tence, as a train enters the stretch from either end, all the signals governing traflic through the stretch in the direction opposite to that in which the train is moving will change to stop indication. Also, with the apparatus thus far described, as a train proceeds through the stretch, the signals in its rear governing trafiic in the direction of movement of the train would change to stop indication and remain there until the train leaves the stretch. Means are provided, however, for at times rendering each of the signal relays for the intermediate signals ineffective to control the signal relay next in the rear, so that as a train pro ceeds through the stretch ,the signals in the rear of the train may change to proceed indication when the train has left the portions of the stretch Which they immediately govern, thereby permitting a following train to proceed through' the stretch at a safe distance from the first train. This means, as here shown, is a branch around the signal relay contact, which controls the signal relay in the rear, This branch is controlled by the polarizedrelay located adjacent the I For example, the branch around contact 17 of relay R is from wire 25 through contact 20 of polarized relay P to wire 31. It will be seen that each polarized relay, when energized to close contact 20,which I shall term the reverse energization of the relay-closes the branch around the contact of the corresponding signal relay and thus renders that relay ineffective to control the signal relay for the signal next in the rear. No polarized relays are provided for the end signals, because in the illustrated embodiment of my invention the corresponding signal relays are not provided with contacts to control other signal relays.

Each polarized relay P is provided with a normal and areverse energization circuit controlled by the adjacently located track relay T and also by a contact of a controller K operated by the adjacent signaL, As here shown each relay P is further controlled by the adjacently located line relay and by an additional contact of controller K, but this supplementary control is not essential to the operation of the signaling system, and is provided for purposes of securing additional features in the operation of the system, as

hereinafter pointed out. The normal energization circuit for relay P for example, is from the middle point of battery B through wire 40, relay P Wire 41, contact 18 of relay R", wire. 50, contact a of controller 1', wire 43, contact 13 of relay T and wire 25 to the positive pole of battery B This normal circuit is provided with a branch which extends from wire 41 through contact 19 of relay R, wire 42, contact 6 of controller K to wire 43. The reverse energization circuit for the relay is from the middle point of battery B contact 19 of relay R wire 42, contact I) of controller K wire 43, contact 14 of relay T, wires H and 29 to the negative pole of battery B. It is apparent that current flows through the wind ing of relay P in one direction or the other according as the normal or the reverse e11er- V gization circuit of relay P is closed, in other words, according as track relay T is energized or deenergized-provided that the circuit of relay P is closed at circuit controller K hand relay R Current through the relay in the normal direction causes such operation of the contact fingers as to open contact '20 and close contact 21, (in which position the contacts are shown on the drawing). Current through the relay in the reverse direction causes the contact fingers to open contact 21 and close contact 20. Contact 6 of controller K is closed during a portion of the movement of signal S from proceed to stop or vice versa, but is open when the signal is at either of these indications. Contact (L of controller K is closed only when the signal is in the stop position.

Each polarized relay is provided with a normal and a reverse energization circuit, which circuits are similar to the circuits just described for relay P The operation of the apparatus during the passage of a westbound car or train through the stretch AB is as follows: As the train enters sub-section AH, it opens track relay T thereby opening at contact 11 the circuit for signal relay R, which in turn causes signal S to change to the stop indication. The opening of contact 12 of track relay T opens the circuit of signal relay R, which latter causes signal S to change to stop. It will be noted that as signal S is changing from the proceed to the stop indication, track relay is energized whereas relay R is open, so that the normal energization circuit of relay l is closed as the contact fii'lger of controller K sweeps over contact segment 0. The contacts of relay 1" should already be in the normal position, as shown in the drawing, but if for any reason they are not, they will be moved there at this time. Thus it is assured that the contacts of relay l are in the proper positions. This feature is conducive to a high degree of safety in the operation of the signaling system. Relay R opens at contact 17 the circuit for relay R, which in turn opens relay R so that signals S and S are caused to assume the stop indication. While signal S is changing to stop, the normal circuit for relay P is temporarily closed in the same manner as was the normal circuit for relay P during the movement of signal S". It will be seen, therefore, that as soon as the train enters sub-section AH, all signals governing traffic in the direction opposite to the direction of movement of the train change to stop indication. As the train enters subsection HC, it-opens track relay T, but this has no effect on the signals, because contacts 11 and 12 of this relay control the same circuits as contacts 11 and 12 of track relay T the closing of back contact 14: of relay T does not close the reverse circuit for relay P, because this circuit is open at controller K. When the train leaves subsection AH relay T closes its contacts but this has no immediate effect on the apparatus. As the train enters sub-section CL, it opens track relay T thereby opening at contact 12 the circuit for signal relay R which causes signal S to change to the stop indication. The opening of contact 11 of track relay T opens at this point the circuit forrelay R, but this has no influence on the signals, because this circuit was already open at'contact 17 of relay R. The opening of contact 17 of relay B would hold open the circuit for signal relay B were not polarized relay P reversed during the movement of signal S from proceed to stop, that is, while the contact finger of controller K is sweeping across segment I). The reverse energization circuit for this relay P has been traced hereinbefore, and, as also pointed'out hereinbefore, when once reversed this relay remains in the reverse position until it is energized in the normal direction. When the entire train leaves sub-section HC, the closing of track-relay T closes the circuit for signal relay B so that signal S then changes to proceed indication, thereby permitting a following westbound car or train to enter the stretch. The closing of track relay T also closes at contact 12 the circuit for signal relay B, so that signal S then changes to the proceed indication. As the train enters sub-section L-D, the opening-of track relay T opens at this point the circuits for signal relays R and R both of which already are deenergized, but otherwise it has no efi'ect on the apparatus. When the train passes out of sub-section CL, track relay T closes its front contacts, but this has no immediate effect on the ap aratus, because the circuits controlled there y are open at other points. As the train enters sub-section D-M, the opening of track relay T opens the circuit of relay R which in turn causes signal S lit to change to the stop indication. During the movement of signal S contactb of circuit controllerK is closed for an interval, and since relays R and T are both open the reverse energization circuit for relay P is momentarily closed so that this relay reverses. Thus relay R closes when relay T is reenergized as the train leaves section LD completely, thereby causing signal S to ,move to the proceed position. Before signal S actually begins to move, however, the normal circuit for relay P isclosed through contact a of controller K for an interval of time suflicient to cause the contacts of relay P to swing back to the 'normal position, this normal circuit being through front contact 18 of relay R con tact a of controller K and front contact 13 of relay T Contact 21 of relay P then completes the circuit for relay R" which is I energized and causes signal-S to indicate proceed. The entrance of the train into section MB causes relay T to 0 en its contacts, and the exit of the train rom section DM causes relay T to close its contacts. Neither operation has any effect on the other apparatus. When the train leaves section M-B, relay T? closes the circuit for relay R so that signal S is moved to the proceed aspect. en relay R closes, and before contact a of circuit. controller K opens, the normal circuit for relay P is closed and the contacts of this relay swing back to the normal position shown on the drawing. The closure of contact 21 of relay 1P completes the circuit of relay R so thatsignal S is brought back to the proceed aspect. Thus all parts of the apparatushave been restored to the positions shown on the drawmg.

The operation of the apparatus during the passage of an eastbound car or train through the stretch is similar to that just explained for the passage of a westbound car or train.

Contacts 21 of relays P are provided to prevent a signal from clearing if the polarized relay which indirectly controls it fails to be restored to the normal position for any cause. Suppose, for instance, that because ofa broken wire in the normal energizing circuit, relay P fails to be brought back to normal when signal S clears. Then relay R would be held open at contact 21 of relay 1 so that signal 5 would remain at stop when the westbound train leaves the stretch. If relay B were not thus controlled by contact21 of relay P signal 8 would change to proceed when the train leaves the stretch. Then, if a westbound train and aneastbourul train should enter stretch A-B simultaneously, the eastbound train would find signal 5* at stop, because signal relay R is opened by relay R", the circuit of which is broken when track relay T is deenergized. The westbound train,

however, would find signal S at proceed because the circuit for signal relay R although opened at contact 17 of relay R, is held closed through contact 20 of relay P vThe westbound train would then pass through block CD at full speed and find signal S at stop. If the engineer of this train should be unable to bringthe train to a standstill before it reaches the signal it would run into the eastbound train which is standing directly behind the signal; Such a condition is prevented by the insertion of contact 21 of relay P in the circuit for relay B, because signal S is thus prevented from clearing when relay P remains in the reversed position.

It will be noted that the signaling system would 0 erate in substantially the manner describe if contacts a of controllers K and contacts 18 and 19 of relays R were omitted from the control circuits of relays P. .In that case each wire 42 would be directly connected to the corresponding rela P, as shown for relay P by a dotted line 42. With such connections, when a train enters sub-section CL, track relay T is, denergized and closes contact 14, so that during the momentary closure of contact a of circuit controller K whilesignal S is movin to the stop'position, relay P is reverse Relay I remains reversed until the normal energization circuit is closed when t-he train has leftsection CD completely, at whlch time relay R is renergized so that signal S moves from stop to proceed. During the momentary closure of contact I) of circuit controller K while signal S is mov-- remain at stop even when there were notrain instretch A-,-B. 'Thussall eastbound trafiic would be kept out offtlia'e' stretch, for the end signals are in general practice socalled absolute signals and should not be passed bya train when in the stop position.

This cannot happen when contact a of controller K is used in conjunctiorrjwith the contacts of relay B? as. described 'hei'einbefore. With this arrangement :lrl'ayl 1 can be brought back to normalwh'en" signal S fails to clear because contact a". ,aii gzilal K is closed while the signal i s-tin "the stop position.

Although I have herein shown and described only one form of signaling system embodyingmy invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track, signals located at intervals throu h the stretch-for governing trafiic in one irection, and other signals located at intervals for governing trafiic in the opposite direction, a signal relay for controlling each signal, track circuits for the stretch including track relays for controlling said signal relays, means for controlling the signal relay for each signal by the signal relay for the signal next in advance governing trafiic in the same direction, means responsive to reversals of current for each signal relay for rendering the relay inefl'ective to control the signal relay for the signal next in the rear, and means for controlling said last-mentioned means by the track relays and the corresponding signal.

2. In combination, a stretch of railway track, signals located at intervals throu h the stretch for governing trafiic in one irection, and other signals located at intervals for governing traffic in the opposite direction, a signal relay for controlling each signal,track circuits for the stretch including track relays for controlling said signal relays, means for controlling the signal relay for each signal by a contact of the signal relay next in advance governing traffic in the same direction, a branch around each of said contacts, a polarized relay for controlling each of said branches, and means for controlling said polarized relays by the track relays and the. corresponding signal.

3. In combination, a stretch of railway track divided into a plurality of sections, a pair of opposing signals located substantially at each junction of adjacent sections for governing traffic in opposite directions, a signal relay for the control of the indication of each signal, track circuits for the sections, each including a track relay for controlling the signal relay for each signal governingtraliic'through the section; means for controlling each signal relay by the signal relay! for the signal next in advance governingjtraflic in the same direction, a polarizedi-felay for eachsignal relay adapted when; energized in one direction to render the latter inefiective to control the signal relay for the sign'al next in the rear, a normal and a reversefenergization circuit for each polarizecirrelay, each normal circuit including ontf-fcontact, of a track relay for the sec ion through which the corresponding signalgoverns traliic,,and a conall tit

said track relay and the said contact controlled by the signal.

4. In combination, two successive sect1ons of a railway track, a signal located adjacent the entrance end of each section, a signal relay for each signal for -'the control thereof, a line circuitfor each signal re- ,lay extending through the corresponding section, track circuits' for the sections including track relays for controlling the line circuits of the signal relays, means for controlling the line circuit for the section in the rear by the line circuit for the section in advance; and a polarized relay for removing the line circuit for the section in the rear from control by the line circuit for the section in "advance, a nor-' 5. In combination, two successive sections of a railway track, signalsfor governing trafiic through said sections in the same direction, a signal relay for controlling each signal, track circuits for-each section, means for governing the signal relay for the section in advance by the track circuits for the section in advance, means for governing the signal relav for the section in the rear by the track circuits of the section in the rear and by said signal relay for the section .in advance, and means selectively responsive to the direction of current flowing therein for shunting the control of the signal relay for the section in the rear from the signal relay for the section in advance when l a train enters the section in advance in the direction governed by the signals.

6. In combination, two successive sections of a railway track, signals for governing traffic through said sections in the same direction, a signal relayior controlling the signal in the rear, track circuits for each section, means for controlling the signal in advance by thetrack circuits of that section, means for controlling the signal relay by the track circuits for the two sections, means responsive to reversals of current for preventing the track'circuit for the section in advance from. controlling the said signal relay when a train enters said section in advance in the direction governed by said si ale.

In combination, two successive sections of a railway track, signals for governing traffic through said sections in one direction, means for the section in advance controlled by the presence or absence of a-train in said section for controlling the signal in advance, means for the section in the rear controlled by the presence or absence of a train inboth sections for controlling the signal in the rear, means responsive to reversals of current for rendering a train entering the section in advance in the direction governed by said signal ineilective in the con trol of said rear signal,

8. In combination, two successive sections of a railway track, signals for governing traffic through said sections in one direction, a track \circuit including a track relay. for the section in advance, a signal relay for said section in-advance controlled by said track relay, means controlled by contactsi of said signal relay for controlling the signal for the section in advance, an electromagnetic translating device responsive to reversals ofcurrent, a normal and a reverse energization circuit for said device; means for controlling said circuits by saidtrack relay and by said signal for the section in advance; means for controlling the signal for the section in the rear by a contact con-.

trolled by said signal relay, and means for shunting the last mentioned contact, said means comprising a contact controlled by said electromagnetic translating device.

9. In combination, a stretch of railway track, signals located at intervals for governing traffic in one direction through the said stretch and other signals located at intervals for governing traflic in the other direction through said stretch, track circuits including track relays for the sections, a signal relay for each signal, means for con trolling each signal by the corresponding signal relay, an electromagnetic translating device for each signal responsive to reversals of current, means for sending current of reverse polarity through said trans-v lating device when a train enters the section guarded by the corresponding signal in the direction governed by said signal,

said means comprising a contact controlled by said signal andclosed when said signal is moving from its proceed to its stop position, a back contact controlled by the adjacent track relay and a back contact controlled by the adjacent signal relay; means for sending current of normal polarity through said translating device when the train passes out of the section immediately guarded by said signal, said means comprising a contact controlled by said signal and closed only when said signal'is in its stop position, afront contact controlled by" the adjacent track relay and a front contact controlled by the adjacent signal relay; means for controlling each signal relay'by a contact of the signal relay corresponding to the signal next in advance controlling traitic in the same direction, by the track relays of the track circuits extending between said signal relays; and by the trans lating. device corresponding to a signal governing trafiic in the opposite direction; and

means for shunting said-last-mentioned signal relay contact when the adjacently located translating device has last been energized by current of reverse polarity.

10.;Incombination, two successiveise ctions of a railway track, signals for govern:

ing traffic through said sections in one "direction, track circuits forjthesections in-;

cluding track relays, a,'signal relay for the section in advance controlled by the track relay for said section, meanscontrolled by contacts of said signal relay for controlling the signal for the section in advance, an

electromagnetictranslating device respon- .sive 'to reversal of current, means for controlling the current through said device,

said means comprlsing a circuit controller. operated by the signal for the section in advance and a contact governed by a track relay for the section in advance; a contact overned by said device and having a normal or a reverse position according to the direction of current last flowing through said device, a circuit for controlling said signal in the .rear and governed by a contact of the track relays forsaid section and a contact of said signal relay, and a shunt around the last-mentioned contact controlled by'the contact .of said translating device.

11. In combination, a stretch of railwaytrack, signals located at intervals in said stretch for governing traffic, in one direction, aslgnal clrcult for each s1gnal,; means for controlling each signal circuit by the,

circuit for the signal next in'ad'vance, means .for each signal circuit responsive to reversals of current and operating when energized in one direction to remove the corresponding signal circuit. from control by the circuit for the signal next in advance,

t and track circuits for the stretch including nal, means for each signal responsive to reversals of current forremoving said signal from control by the track circuits lying in'advance of the signal next in advance, means controlled by the track circuits for energizing said means for each signal in such direction as to effect said control when 'a car or train passes the signal next in advance, and for energizing said means in the opposite direction when the car or train passes-the second signal in advance of the one for which such means is provided.

13. In combination, a stretch of railway track, signals located at intervals in said stretch for governing traiiic through the stretch in one direction, track circuits for the'stretch, means for controlling each signal by all of the track circuits for the portion of the stretch in advance of such signal,

andmeans for each signal and responsive to reversals of current and operating when energized in the proper direction to remove the corresponding signal from control by the track circuits lying in advance of the next signal in advance, said last-mentioned means being also controlled by said track circuits.

In testimony whereof I aflix my signature 1n presence of two yvltnesses.

RONALD A. McCANN. Witnesses:

A. L. VENCILL, A, C. NQLTE, 

